Pipe fittings

ABSTRACT

Improvements to stab-type pipe fittings capable of being inserted onto plastic pipes and provide a leak proof connection are provided. The pipe fittings have an outer casing with pipe ports, a hollow inner casing positioned within the outer casing, a pipe gripper and stiffener positioned within the inner casing. The pipe ports have an elongated lip that straightens a pipe inserted into the fitting. The stiffener provides a multi-compression seal to facilitate the leak proof connection.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending application Ser. No.15/644,549 filed on Jul. 7, 2017 and claims benefit from U.S.Provisional Application Ser. No. 62/361,299 filed on Jul. 12, 2016 theentire contents of both are herein incorporated by reference.

BACKGROUND Field

The present disclosure relates to stab-type pipe fittings designed tocouple one or more plastic pipes to a fitting, and more particularly tostab-type pipe fittings with an improved seal between the fitting andthe pipe.

Description of the Related Art

Stab-type pipe fittings are designed to be inserted manually onto theend of a length of plastic pipe or between lengths of plastic pipes.Generally, due to mechanisms within stab-type fittings, after a fittingis inserted onto a length of plastic pipe the fitting is not intended tobe pulled off of the pipe, such that the way to remove the fitting is tocut the pipe. Thus, stab-type pipe fittings are a one-time use pipefitting that facilitates quick and easy connection to plastic pipes. Ifproperly installed, stab-type pipe fittings form a sealed, leak proofpathway between the plastic pipes inserted into the fittings.

SUMMARY

The present disclosure provides exemplary embodiments of improvements tostab-type pipe fittings that are capable of being inserted onto plasticpipes and provide a leak proof connection. In one exemplary embodiment,the pipe fitting comprises an outer casing having at least one pipe portproviding a passageway for a pipe to be passed into the outer casing, ahollow inner casing positioned within the outer casing and having atleast one opening aligned with the at least one pipe port, at least onegripper positioned within the inner casing, and a stiffener positionedat least partially within the inner casing and the at least one gripperopening. The at least one pipe port comprises an elongated lip and aport opening forming at least part of the passageway.

The at least one gripper is positioned within the inner casing and hasan opening aligned with the at least one pipe port. The at least onegripper includes one or more reverse serrations that can flex when apipe is passed through the at least one gripper opening imparting littleresistance to the forward advancement of the pipe into the at least onegripper while imparting sufficient resistance to rearward movement ofthe pipe to prevent withdrawal of the pipe from the at least onegripper.

The stiffener has at least a pair of sealing members each positionedwithin a groove in an outer surface of the stiffener such that when apipe is passed over the stiffener and sealing members the sealingmembers can contact an interior wall of the pipe to provide a sealbetween the pipe and the stiffener. In one embodiment, the pair ofsealing members have the same diameter and the grooves have differentdimensions. In another embodiment, the pair of sealing members havedifferent diameters and the grooves have the same dimensions.

In another embodiment, the stiffener has at least three sealing memberseach positioned within a groove in an outer surface of the stiffenersuch that when a pipe is passed over the stiffener and sealing membersthe sealing members can contact an interior wall of the pipe to providea seal between the pipe and the stiffener. In one embodiment, the atleast three sealing members have the same diameter and the grooves havedifferent dimensions. In another embodiment, the at least three sealingmembers have different diameters and the grooves have the samedimensions.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the present disclosure and many of theattendant advantages thereof will be readily obtained as the samebecomes better understood by reference to the following detaileddescription when considered in connection with the accompanyingdrawings, wherein:

FIG. 1 is a perspective view of an exemplary embodiment of a pipefitting according to the present disclosure;

FIG. 2 is a cross-sectional view of the pipe fitting of FIG. 1 takenfrom line 2-2 and illustrating a pipe being inserted into the fitting;

FIG. 3 is a perspective view of the pipe fitting of FIG. 1 with aportion of an outer casing removed to reveal an inner casing encasedwith the outer casing;

FIG. 4 is an exploded view of the inner casing of FIG. 3 revealing apair of grippers separated by a hub and a stiffener within the innercasing;

FIG. 5 is a cross-sectional view of the stiffener of FIG. 4,illustrating two sealing members positioned around the stiffener;

FIG. 6 is an enlarged view of a portion of the stiffener of FIG. 5,illustrating two sealing members having different diameters incircumferential grooves having the same depth;

FIG. 7 is a cross-sectional view of the pipe fitting of FIG. 1,illustrating pipes having a minimum internal diameter capable of fittingover the stiffener;

FIG. 8 is an enlarged view of a portion of the pipe fitting of FIG. 7,illustrating the two sealing members engaging an inner wall of the pipehaving the minimum internal diameter;

FIG. 9 is a cross-sectional view of the pipe fitting of FIG. 1,illustrating pipes having a maximum internal diameter capable of fittingover the stiffener;

FIG. 10 is an enlarged view of a portion of the pipe fitting of FIG. 9,illustrating the two sealing members engaging an inner wall of the pipeshaving the maximum internal diameter;

FIG. 11 is a cross-sectional view of another exemplary embodiment of thestiffener of FIG. 4, illustrating three sealing members positionedaround the stiffener;

FIG. 12 is an enlarged view of a portion of the stiffener of FIG. 11,illustrating three sealing members having different diameters incircumferential grooves having the same depth;

FIG. 13 is an enlarged view of a portion of the pipe fitting of FIG. 7having a stiffener of FIG. 11, illustrating the three sealing membersengaging an inner wall of the pipe having the minimum internal diameter;

FIG. 14 is an enlarged view of a portion of the pipe fitting of FIG. 9having a stiffener of FIG. 11, illustrating the three sealing membersengaging an inner wall of the pipes having the maximum internaldiameter;

FIG. 15 is a cross-sectional view of another exemplary embodiment of astiffener according to the present disclosure, illustrating two sealingmembers positioned around the stiffener;

FIG. 16 is an enlarged view of a portion of the stiffener of FIG. 15,illustrating sealing members have the same diameter in circumferentialgrooves having different depths;

FIG. 17 is a cross-sectional view of the pipe fitting of FIG. 1 and thestiffener of FIG. 15, illustrating pipes having a minimum internaldiameter capable of fitting over the stiffener;

FIG. 18 is an enlarged view of a portion of the pipe fitting of FIG. 17,illustrating the two sealing members engaging an inner wall of the pipeshaving the minimum internal diameter;

FIG. 19 is a cross-sectional view of the pipe fitting of FIG. 1 and thestiffener of FIG. 15, illustrating pipes having a maximum internaldiameter capable of fitting over the stiffener;

FIG. 20 is an enlarged view of a portion of the pipe fitting of FIG. 19,illustrating the two sealing members engaging an inner wall of the pipeshaving the maximum internal diameter;

FIG. 21 is a cross-sectional view of another exemplary embodiment of thestiffener of FIG. 4, illustrating three sealing members positionedaround the stiffener;

FIG. 22 is an enlarged view of a portion of the stiffener of FIG. 21,illustrating sealing members have the same diameter in circumferentialgrooves having different depths;

FIG. 23 is an enlarged view of a portion of the pipe fitting of FIG. 7having a stiffener of FIG. 21, illustrating the three sealing membersengaging an inner wall of the pipe having the minimum internal diameter;

FIG. 24 is an enlarged view of a portion of the pipe fitting of FIG. 9having a stiffener of FIG. 21, illustrating the three sealing membersengaging an inner wall of the pipes having the maximum internaldiameter;

FIG. 25 is a perspective view of another exemplary embodiment of a pipefitting according to the present disclosure;

FIG. 26 is a cross-sectional view of the pipe fitting of FIG. 25 takenalong line 26-26;

FIG. 27 is a front perspective view of another exemplary pipe fittingaccording to the present disclosure;

FIG. 28 is a cross-sectional view of the pipe fitting of FIG. 27 takenalong line 28-28;

FIG. 29 is a front perspective view of another exemplary pipe fittingaccording to the present disclosure;

FIG. 30 is a side view of the pipe fitting of FIG. 29;

FIG. 31 is a front perspective view of another exemplary pipe fittingaccording to the present disclosure; and

FIG. 32 is a side view of the pipe fitting of FIG. 31.

DETAILED DESCRIPTION

The present disclosure provides various embodiments of improvements tostab-type pipe fittings that are capable of being inserted onto plasticpipes and provide a leak proof connection. Exemplary types of thestab-type pipe fittings used to connect to plastic pipe include, but arenot limited to, couplers, elbows (also known as “L's”), Tee's, reducersand end caps. Those skilled in the art would readily recognize that thefeatures of the improvements to stab-type pipe fittings disclosed hereinmay be incorporated into any stab-type pipe fitting, including thosenoted above. For ease of description, the present disclosure may referto stab-type pipe fittings as the pipe fitting in the singular or pipefittings in the plural.

In the exemplary embodiment shown in FIGS. 1-4, the pipe fitting is acoupler used to join two plastic pipes together. Thus, for this part ofthe description, the pipe fitting will be referred to as the coupler.The coupler 10 includes an outer casing or shell 20, an inner casing orshell 40, one or more grippers 70, and one or more stiffeners 90. Theone or more grippers 70 and one or more stiffeners 90 are encased withinthe inner casing 40 and the inner casing 40 is encased within the outercasing 20.

The outer casing 20 has a body 22 and one or more pipe ports 24. Thebody 22 has a hollow interior that receives the inner casing 40 tosurround the inner components of the coupler 10, as seen in FIG. 3. Thebody 22 has one or more openings 26 each configured to permit a plasticpipe to pass into the body 22. In the embodiment shown in FIG. 2, thebody 22 has two openings 26. It should be noted that for certain typesof pipe fittings the body 22 may have more than two openings, such asTee type pipe fittings, and for other types of pipe fittings the body 22may have one opening, such as end cap type pipe fittings. The body 22 ismade of a sufficiently rigid material to provide a protective casing forthe inner components of the coupler 10.

Each of the one or more pipe ports 24, which may also be referred to asa moisture lip, have a center opening 30 and an elongated port lip 34.The center opening 30 is aligned with an opening 26 in the body 22. Inthe exemplary embodiment of a coupler as the pipe fitting, there are twopipe ports 24. However, it should be noted that for certain types of thepipe fittings the outer casing 20 may have more than two pipe ports 24,such as in Tee type pipe fittings, and in other types of pipe fittingsthe outer casing 20 may have one pipe port, such as end cap type pipefittings. Each pipe port lip 34 may be integrally formed into the outercasing body 22 such that the openings 26 and 30 are one continuouspassageway into the outer casing 20, or each pipe port lip 34 may besecured to the outer casing body 22 using, for example, adhesives, weldsor mechanical fasteners. Where a pipe port 24 is secured to the outercasing body 22, the center opening 30 is aligned with an outer casingopening 26 to form a passageway into the outer casing 20. Providing apassageway into the outer casing 20 permits a plastic pipe to pass froma pipe port 24 through the opening 26 into the outer casing 20, andeventually into the inner casing 40.

As noted, the pipe port lip 34 is an elongated lip that extends from theouter casing body 22. As shown in FIG. 1, each elongated lip 34 extendsfrom the outer casing body 22 a distance D1 that may range from about ⅛of an inch to about 2 inches. Each pipe port lip 34 is configured toreceive a pipe 200, seen for example in FIG. 2, and the elongated natureof the pipe port lip 34 aligns and straightens the pipe 200 as it entersthe coupler 10 prior to the pipe passing over the stiffener 90. Theelongated pipe port lip 34 also ensures that the pipe 200 remainssubstantially straight within the coupler 10. By maintaining thestraightness of the pipe 200 within the coupler 10, the pipe port lip 34also ensures that an even radial compression can be maintained betweenthe sealing members of the stiffener 90 and the inner diameter of thepipe 200 even under bending loads. To provide additional structuralintegrity to each pipe port 24, one or more gussets 38 may be positionedaround the perimeter of each pipe port lip 34. The gussets 38 may beintegrally formed into the pipe port lip 34 and the outer casing body22, or the gussets 38 may be secured to the pipe port lip 34 and theouter casing body 22 using, for example, adhesives, welds or mechanicalfasteners. To facilitate the described pipe straightening, the pipe portlip 34 and gussets 38, if used, are preferably made of a sufficientlyrigid material.

Referring to FIGS. 2 and 4, as noted, the inner casing 40 of the coupler10 encases the gripper 70 and at least a portion of the stiffener 90.The inner casing 40 is a hollow casing or shell that may be formed as asingle casing or as a multi-component casing coupled together. The typeof pipe fitting may determine whether the inner casing 40 is a singlecasing or a multi-component casing. For example, the inner casing 40 maybe a multi-component casing where the pipe fitting has two or more pipeports 24, such as in coupler type pipe fittings, elbow type pipefittings, Tee type pipe fittings, or reducer type pipe fittings. Asanother example, where the pipe fitting has one pipe port 24, such as inend cap type pipe fittings, the inner casing 40 may be a single casing.In the embodiment of a coupler shown in FIGS. 1-4, the inner casing 40is a multi-component casing having two casing members 42 that arecoupled within the outer casing 20 to form the inner casing 40. In theexemplary embodiment of an elbow shown in FIGS. 19 and 20, the innercasing 40 is a multi-component casing having two casing members 42 and amain body between the casing members to effect a 90-degree angle of theelbow shown. Thus, in this exemplary embodiment the casing members 42and the main body form the inner casing 40.

Continuing to refer to FIGS. 2-4, each casing member 42 has an inner end46 and an outer end 48. The inner end 46 has a circumferential ring 50extending beyond an outer surface of the casing member 42. The ring 50is aligned with the opening 26 in the outer casing body 22 so that apipe 200 passing through a pipe port 24 and an opening 26 can pass intothe hollow portion of the casing member 42. On the inside of thecircumferential ring 50 is a circumferential notch 52. In the embodimentof FIGS. 1-4, the circumferential notch 52 is used to receive a hub 60that maintains the gripper 70 and the stiffener 90 within the innercasing 40. In the exemplary embodiment of the coupler 10, the notches 52of each casing member 42 when joined form a channel 44 to receive anouter wall 62 of the hub 60. The hub 60 may be secured within thechannel 44 by, for example, a friction fit, adhesive, weld or mechanicalfastener. The hollow portion of the inner casing members 42 extends fromthe circumferential notch 52 to a circumferential ring 54 at the outerend 48. The hollow portion of the casing members 42 has a straightportion starting at the notch 52 followed by a tapered portion, e.g., afrusto-conical surface, that ends at the circumferential ring 54. Thecircumferential ring 54 maintains the gripper 70 within the inner casing40. The outer end 48 includes an opening 56 that can receive thestiffener 90 and a pipe 200.

It is noted that for the coupler 10, two grippers 70 are incorporatedinto the coupler 10, one in each casing member 42. Each gripper 70 hasan opening 72 that is aligned with a pipe port 24, and includes reverseserrations that can flex when a pipe 200 is passed into the gripper 70imparting little resistance to the forward advancement of the pipe 200into the inner casing member 42, while imparting sufficient resistanceto rearward movement of the pipe to prevent withdrawal of the pipe 200from the inner casing 40. In instances where a pipe fitting has morethan two pipe ports 24, e.g., a Tee type pipe fitting, there would bemore than two grippers 70 within the inner casing 40, with each gripper70 opening aligned with a pipe port 24. In instances where a pipefitting has one pipe port 24, e.g., an end cap type pipe fitting, therewould be one gripper 70 having an opening 30 that is associated with thepipe port 24.

The gripper 70 is a hollow member having an inner end 70 a that isconfigured to abut hub 60 and an outer end 70 b. The side of the gripper70 opposite the hub 60 is tapered, generally a frusto-conical shape thatcoincides with the shape and slope of a tapered edge within the casingmember 42 adjacent the ring 54. Each gripper 70 is preferablyconstructed of material that is harder than the pipe. Having a taperedend of the gripper 70 that is shaped to coincide with the tapered edgeof the casing member 42 allows the gripper 70 to engage the casingmember 42 in the event a pipe 200 is pulled in an attempt to withdrawthe pipe 200 from the coupler 10. When the gripper 70 tapered endengages the tapered edge of the casing member 42, the gripper 70 iscaused to constrict so that the serrations more tightly bite into thepipe 200 to prevent the withdrawal of the pipe from the coupler 10.

Referring to FIGS. 5 and 6, the stiffener 90 has two sets of two sealingmembers 94 and 96 positioned along the stiffener 90. However, it shouldbe understood that each set may have more than two sealing members 94and 96 positioned along the stiffener 90. For example, FIGS. 11 and 12show a stiffener 90 having two sets of three sealing members 94, 95 and96 positioned along the stiffener 90. The stiffener 90 is preferably atubular structure constructed of rigid material, such as plastic ormetal. The stiffener 90 is positioned within the inner casing 40 so thatone end 98 is positioned in alignment with the opening 26 in the outercasing 20 and the opening 56 in one inner casing member 42. The otherend 100 of the stiffener 90 is positioned in alignment with anotheropening 26 in the outer casing 20 and opening 56 in the other innercasing member 42. The stiffener 90 has an external diameter that issmaller than the allowable variation in the internal diameter D2′ (seenin FIG. 7) and D2″ (seen in FIG. 9) of the pipes 200 that may beinserted into the coupler 10 and pushed onto the stiffener 90. As pipes200 are inserted into a pipe port 24, the corresponding opening 26 inthe outer casing 20 and the corresponding opening 56 in the other innercasing member 42, they can be pushed onto the ends 98 or 100 of thestiffener 90. As noted above with reference to FIG. 2, as a pipe 200 ispushed into a pipe port 24, the pipe port 24 straightens the pipe beforethe pipe is passed over the stiffener 90.

As described above, the stiffener 90 is secured within coupler 10 usingthe hub 60 that encircles the stiffener 90 approximately midway betweenends 98 and 100. To assist in securing the hub 60 to the stiffener 90, aknurled area 102 may be formed on the outer surface of the stiffener 90,as shown in FIG. 5. The knurled area 102 helps maintain the hub 60 inposition on the stiffener 90. In another embodiment, the hub 60 may bebonded to the stiffener 90 at the knurled area 102 or instead ofincluding a knurled area.

To seal plastic pipes 200 within the coupler 10 using the stiffener 90of FIGS. 5 and 6, the stiffener 90 includes two sets of twocircumferential grooves 104 and 106 to support the sealing members 94and 96, which may be, for example, elastomeric O-rings. The sealingmembers 94 and 96 provide a multi-compression feature where both sealingmembers contact the internal walls of the plastic pipe 200 connected tothe coupler 10 to provide a liquid or gas proof seal. In this exemplaryembodiment, each pair of circumferential grooves 104 and 106 andcorresponding sealing members 94 and 96 are positioned on the stiffener90 on opposite sides of the location where the hub 60 would be locatedrelative to the stiffener 90, or in other words on opposite sides of theknurled area 102 if the stiffener 90 has a knurled area 102. Thecircumferential grooves 104 and 106 are formed in an outer surface ofthe stiffener 90, as shown in FIGS. 5 and 6. Each pair ofcircumferential grooves 104 and 106 may also be referred to as an innercircumferential groove 104 and an outer circumferential groove 106. Thecircumferential grooves 104 and 106 are spaced apart a distance “D3”that may range from about 5 mm to about 50 mm. To seal plastic pipes 200within the coupler 10 using the stiffener 90 of FIGS. 11 and 12, thestiffener includes two sets of three circumferential grooves 104, 105and 106 to support the sealing members 94, 95 and 96, which may be, forexample, elastomeric O-rings. The sealing members 94, 95 and 96 providea multi-compression feature where all three sealing members may contactthe internal walls of the plastic pipe 200 connected to the coupler 10to provide a liquid or gas proof seal. In this exemplary embodiment,each pair of circumferential grooves 104, 105 and 106 and correspondingsealing members 94, 95 and 96 are positioned on the stiffener 90 onopposite sides of the location where the hub 60 would be locatedrelative to the stiffener 90, or in other words on opposite sides of theknurled area 102 if the stiffener 90 has a knurled area 102. Thecircumferential grooves 104, 105 and 106 are formed in an outer surfaceof the stiffener 90, as shown in FIGS. 11 and 12. Each pair ofcircumferential grooves may also be referred to as an innercircumferential groove 104, an intermediate circumferential groove 106,and an outer circumferential groove 105. The circumferential grooves104, 105 and 106 are spaced apart a distance “D3” that may range fromabout 5 mm to about 50 mm.

The multi-compression feature of the present disclosure permits the pipefitting, e.g., the coupler 10, to connect to pipes 200 with variationsin the internal diameter of the pipe and maintain a sufficient seal toprevent liquid or gas leakage. For example, one vendor could make a 1″polyethylene pipe with an internal diameter of 1.082 inches, and anothervendor could make a 1″ polyethylene pipe with an internal diameter 1.044inches. Both pipes 200 would be within the dimensional requirements forsuch 1″ pipes, but that variation in the internal diameters may besufficient to impact the seal between the pipe and the fitting. Asanother example, when a 1″ polyethylene pipe is manufactured the 1″ pipemay have variations in the inner diameter of the pipe due toirregularities in the manufacturing process.

In addition, the multi-compression feature of the present disclosurepermits the pipe fitting, e.g., the coupler 10, to maintain the sealbetween the fitting and the pipe 200 in an expanded temperature range.For example, in one temperature range, e.g., −40 degrees F. to 100degrees F., a sealing member 94, 95 or 96, such as an elastomericO-ring, may retain its hardness, elongation and compressive properties,but at a different temperature range, e.g., 100 degrees F. to 200degrees F., the sealing member's hardness, elongation and compressiveproperties may change. Using the multi-compression feature of thepresent disclosure allows the use of different size sealing members 94,95 or 96 or positions the sealing members differently to meet potentialvariations in the sealing members that may be caused by temperaturefluctuations.

To be able to seal pipes 200 with variations in their internal diameterand/or in expanded temperature range scenarios, the stiffener 90 shownin FIGS. 5 and 6, for example, may have circumferential grooves 104 and106 that are the same size while the sealing members 94, 95 or 96, e.g.,elastomeric O-rings, are different in sizes. To illustrate,circumferential grooves 104 and 106 have a width W1 that may range fromabout 1 mm to about 20 mm, and a height H1 that may range from about 1mm to about 20 mm. The sealing members 94 and 96 are different in thatthe outer sealing member 96 is smaller than the inner sealing member 94to facilitate easier insertion of a pipe 200 onto the stiffener 90. Inthis embodiment and referring to FIGS. 7 and 8, a pipe 200 having aminimum internal diameter variation D2′ that may fit over the stiffener90 causes the sealing members 94 and 96 to compress to a maximumcompression to seal the pipe 200 relative to the stiffener 90. In thisexample, the sealing member 94 compresses more than sealing member 96,as shown. Similarly, and referring to FIGS. 9 and 10, a pipe 200 havinga maximum internal diameter variation D2″ that may fit over thestiffener 90 causes the sealing members 94 and 96 to compress to aminimum compression to seal the pipe 200 relative to the stiffener 90.In this example, the sealing member 94 compresses slightly more thansealing member 96, as seen in FIGS. 9 and 10.

To be able to seal pipes 200 with variations in their internal diameterand/or in expanded temperature range scenarios, the stiffener 90 shownin FIGS. 11 and 12, for example, may have circumferential grooves 104,105 and 106 that are the same size while the sealing members 94, 95 or96, e.g., elastomeric O-rings, are different in sizes. To illustrate,circumferential grooves 104, 105 and 106 have a width W1 that may rangefrom about 1 mm to about 20 mm, and a height H1 that may range fromabout 1 mm to about 20 mm. The sealing members 94, 95 and 96 aredifferent in that the outer sealing member 95 is smaller than theintermediate sealing member 96, which is smaller than the inner sealingmember 94 to facilitate easier insertion of a pipe 200 onto thestiffener 90. In this embodiment and referring to FIG. 13, a pipe 200having a minimum internal diameter variation D2′ that may fit over thestiffener 90 causes the sealing members 94, 95 and 96 to compress to amaximum compression to seal the pipe 200 relative to the stiffener 90.In this example, the sealing member 96 compresses more than sealingmember 95, and the sealing member 94 compresses more than sealing member96, as shown. Similarly, and referring to FIG. 14, a pipe 200 having amaximum internal diameter variation D2″ that may fit over the stiffener90 causes the sealing members 94 and 96 to compress to a minimumcompression while sealing member 95 does not engage the pipe 200 so thatsealing members 94 and 96 seal the pipe 200 relative to the stiffener90. In this example, the sealing member 94 compresses slightly more thansealing member 96, as seen in FIG. 14.

Referring now to FIGS. 4, 15 and 16, another exemplary embodiment of astiffener 90 for sealing pipes 200 with variations in their internaldiameter and/or in expanded temperature range scenarios is shown. Inthis embodiment, the stiffener 90 has two sets of two circumferentialgrooves 104 and 106 that differ in size but receive sealing members 94or 96 having the same size, e.g., the same diameter. To illustrate,circumferential grooves 104 and 106 have a width W2 that may range, forexample, from about 1 mm to about 10 mm, but circumferential groove 104has a height H2 that may range from about 0.6 mm to about 10 mm, whilecircumferential groove 106 has a height H3 that may range from about 0.9mm to about 11 mm. The two sets of sealing members 94 and 96, e.g.,elastomeric O-rings, are the same diameter size, e.g., the samediameter. As a result, and referring to FIGS. 17 and 18, a pipe 200having a minimum internal diameter variation D2′ that may fit over thestiffener 90 causes the sealing members 94 and 96 to compress to amaximum compression to seal the pipe 200 relative to the stiffener 90.In this example, the sealing member 94 compresses more than sealingmember 96. Similarly, and referring to FIGS. 19 and 20, a pipe 200having a maximum internal diameter variation D2″ that may fit over thestiffener 90 causes the sealing members 94 and 96 to compress to aminimum compression for this embodiment to seal the pipe 200 to thestiffener 90. In this example, the sealing member 94 compresses morethan sealing member 96.

Referring now to FIGS. 21 and 22, another exemplary embodiment of astiffener 90 for sealing pipes 200 with variations in their internaldiameter and/or in expanded temperature range scenarios is shown. Inthis embodiment, the stiffener 90 has two sets of three circumferentialgrooves 104, 105 and 106 that differ in size but receive sealing membershaving the same size, e.g., the same diameter. To illustrate,circumferential grooves 104, 105 and 106 have a width W2 that may rangefrom about 1 mm to about 10 mm, but circumferential groove 104 has aheight H2 that may range from about 0.6 mm to about 10 mm, whilecircumferential groove 106 has a height H3 that may range from about 0.9mm to about 11 mm, while circumferential groove 105 has a height H4 thatmay range from about 1.2 mm to about 12 mm. The two sets of sealingmembers 94, 95 and 96, e.g., elastomeric O-rings, are the same diametersize, e.g., the same diameter. As a result, and referring to FIG. 23, apipe 200 having a minimum internal diameter variation D2′ that may fitover the stiffener 90 causes the sealing members 94, 95 and 96 tocompress to a maximum compression to seal the pipe 200 relative to thestiffener 90. In this example, the sealing member 94 compresses morethan sealing member 96, and the sealing member 96 compresses more thansealing member 95. Similarly, and referring to FIG. 24, a pipe 200having a maximum internal diameter variation D2″ that may fit over thestiffener 90 causes the sealing members 94 and 96 to compress to aminimum compression while sealing member 95 does not engage the pipe 200so that sealing members 94 and 96 seal the pipe 200 relative to thestiffener 90. In this example, the sealing member 94 compresses morethan sealing member 96.

While the stiffener and sealing members that provide themulti-compression feature of the present disclosure are shown as havingtwo or three sealing members on each side of the stiffener, the presentdisclosure contemplates using more than three sealing members on eachside of the stiffener.

Turning to FIGS. 25 and 26, another exemplary embodiment of a pipefitting according to the present disclosure is shown. In the exemplaryembodiment shown, the pipe fitting is a coupler 120 that is used to jointwo plastic pipes 200 together. Thus, for this part of the description,the pipe fitting will be referred to as the coupler 120. The coupler 120includes an outer casing or shell 20, an inner casing or shell 40, agripper 70, and a stiffener 130. In this exemplary embodiment, the outercasing 20 is substantially similar to the outer casing 20 describedabove, except that the pipe port lips 34 are not an elongated body. Inthis exemplary embodiment, the pipe ports lips 34 are more likesnub-nose bodies similar to those in conventional stab-type pipefittings. In addition, the inner casing 40 and gripper 70 are the sameas the inner casing and gripper described above and for ease ofdescription are not repeated. In this embodiment, the stiffener 130 isan elongated stiffener that extends outside the outer casing 20 adistance D4 which may be at least about 1 inch. The elongated stiffener130 ensures that a pipe 200 connected to the coupler 120 is straight atthe point where the sealing members 94 and 96 engage the inner wall ofthe pipe 200. To seal the pipe 200 to the stiffener 130, the embodimentsof the circumferential grooves 104 and 106 and the sealing members 94and 96 described above may be used and are not repeated. However, asnoted above, while the stiffener 130 and sealing members 94 and 96 thatprovide the multi-compression feature of the present disclosure areshown in FIGS. 25 and 26 as having two sealing members 94 and 96 on eachside of the stiffener 130, the present disclosure contemplates usingmore than two sealing members on each side of the stiffener 130, such asthree sealing members on each side of the stiffener 130.

Referring now to FIGS. 27 and 28, another exemplary embodiment of a pipefitting according to the present disclosure is shown. In this exemplaryembodiment, the pipe fitting is an elbow 140 used to join two plasticpipes together at an angle. Examples of elbows include 90 degree elbows,45 degree elbows and 22 degree elbows. Thus, for this part of thedescription, the pipe fitting will be referred to as the elbow 140 wherelike numbered components have like functions as described above withreference to FIGS. 1-26. The outer casing 20 in this exemplaryembodiment is shaped as an elbow with the desired angle, here 90degrees. The elbow 140 in this embodiment has two pipe ports 24. Toaccommodate the bend of the elbow, the casing members 42 of the innercasing 40 are separated and a main body 142 having fluid or gaspassageway 144 is inserted between the casing members 42 which togetherform the inner casing 40. Retained within each casing member 42 is agripper 70 having the components and functions as described above.

In this exemplary embodiment, two stiffeners 150 are provided, where onestiffener 150 is associated with one casing member 42 and the otherstiffener 150 is associated with the other casing member 42. As noted,to connect one stiffener 150 to the other stiffener 150 the inner casing40 includes the main body 142 having a fluid or gas passageway 144 thatprovides a conduit in the shape of the angle of the elbow 140, e.g., 90degrees, to permit fluid or gas to pass from one stiffener 150 to theother stiffener 150, and thus from one pipe 200 to another pipe 200.Each stiffener 150 is substantially similar to a portion of thestiffener 90 described above. More specifically, each stiffener 150 is atubular member made of a rigid material, and includes at least twosealing members, e.g., sealing members 94 and 96, supported within atleast two corresponding circumferential grooves, e.g., grooves 104 and106, as described above. However, as noted above, while the stiffener150 and sealing members 94 and 96 that provide the multi-compressionfeature of the present disclosure are shown in FIGS. 27 and 28 as havingtwo sealing members 94 and 96 on each side of the stiffener 150, thepresent disclosure contemplates using more than two sealing members oneach side of the stiffener 150, such as three sealing members on eachside of the stiffener 150. To secure the stiffener 150 within the innercasing 40, an end 154 of the stiffener 150 may include a knurled area156 that secures the stiffener 150 within a hollow portion of the mainbody 142 by, for example, a friction fit as shown in FIG. 21. In anotherembodiment, the stiffener 150 may be secured within the hollow portionof the main body 142 using an adhesive.

Referring now to FIGS. 29 and 30, another exemplary embodiment of a pipefitting according to the present disclosure is shown. In this exemplaryembodiment, the pipe fitting is a Tee used to join three plastic pipestogether. Thus, for this part of the description, the pipe fitting willbe referred to as the Tee 160 where like numbered components have likefunctions as described above with reference to FIGS. 1-20. The outercasing 20 in this exemplary embodiment is in the shape of a “T”. In thisembodiment, there are three casing members 42 to accommodate the bendsof the Tee. The casing members 42 are separated by a main body 142having fluid or gas passageway inserted between the casing members 42similar to the embodiment described with reference to the elbow 140 ofFIGS. 25 and 26, but adopted for a Tee. Together the casing members 42and main body 142 form the inner casing 40. Retained within each casingmember 42 is a gripper having the function as the gripper 70 describedabove.

In this exemplary embodiment, three stiffeners 150 similar to thestiffeners 150 described above are provided, where one stiffener 150 isassociated with one casing member 42. As noted, to connect one stiffener150 to the other stiffeners the inner casing 40 includes the main body142 that provides a conduit in the shape of a Tee to permit fluid or gasto pass from one stiffener 150 to the other stiffeners 150. As noted,each stiffener is substantially similar to the stiffener 150 describedabove with reference to FIG. 26. More specifically, each stiffener 150is a tubular member made of a rigid material, and includes at least twosealing members, e.g. sealing members 94 and 96, supported within atleast two corresponding circumferential grooves, e.g., grooves 104 and106, as described above. However, as noted above, while the stiffener150 and sealing members 94 and 96 that provide the multi-compressionfeature of the present disclosure are shown in FIGS. 29 and 30 as havingtwo sealing members on each side of the stiffener 150, the presentdisclosure contemplates using more than two sealing members on each sideof the stiffener 150, such as three sealing members on each side of thestiffener. To secure the stiffener 150 within the inner casing 40, anend 154 of the stiffener 150 may include a knurled area 156 that securesthe stiffener 150 within a hollow portion of the main body by a frictionfit. In another embodiment, the stiffener 150 may be secured within thehollow portion of the main body using an adhesive.

Referring now to FIGS. 31 and 32, another exemplary embodiment of a pipefitting according to the present disclosure is shown. In this exemplaryembodiment, the pipe fitting is an end cap 180 used to terminate aplastic pipe. Thus, for this part of the description, the pipe fittingwill be referred to as the end cap 180 where like numbered componentshave like functions as described above with reference to FIGS. 1-30. Theouter casing 20 in this exemplary embodiment has a closed side 23 and aside with a pipe port 24. In this exemplary embodiment, there is onecasing member forming the inner casing 40 within the outer casing 20.Encased within the inner casing 40 is a gripper similar to gripper 70described above and shown in FIG. 4, and a stiffener 150 similar tostiffener 150 described above and shown in FIG. 26. More specifically,the stiffener is a tubular member made of a rigid material, and includesat least two sealing members, e.g., sealing members 94 and 96, supportedwithin at least two corresponding circumferential grooves, e.g., grooves104 and 106, as described above. However, as noted above, while thestiffener 150 and sealing members 94 and 96 that provide themulti-compression feature of the present disclosure are shown in FIGS.31 and 32 as having two sealing members on each side of the stiffener,the present disclosure contemplates using more than two sealing memberson each side of the stiffener, such as three sealing members on eachside of the stiffener. To secure the stiffener 150 within the innercasing 40, an end 154 of the stiffener 150 may include a knurled area156 that secures the stiffener 150 within a hollow portion of the casingmember 42 by a friction fit. In another embodiment, the stiffener 150may be secured within the hollow portion of the casing member 42 usingan adhesive.

It is noted that a more detailed description of the inner casing andgripper, as well as portions of the outer casing and stiffener describedherein is are described in commonly owned U.S. Pat. No. 5,692,785 whichis incorporated herein in its entirety by reference.

As shown throughout the drawings, like reference numerals designate likeor corresponding parts. While illustrative embodiments of the presentdisclosure have been described and illustrated above, it should beunderstood that these are exemplary of the disclosure and are not to beconsidered as limiting. Additions, deletions, substitutions, and othermodifications can be made without departing from the spirit or scope ofthe present disclosure. Accordingly, the present disclosure is not to beconsidered as limited by the foregoing description.

What is claimed is:
 1. A pipe fitting comprising: an outer casing havingat least one pipe port providing a passageway for a pipe to be passedinto the outer casing, wherein the at least one pipe port comprises anelongated lip and a port opening forming at least part of thepassageway; a hollow inner casing positioned within the outer casing andhaving at least one opening aligned with the at least one pipe port; atleast one gripper positioned within the inner casing and having anopening aligned with the at least one pipe port, the at least onegripper includes one or more reverse serrations that can flex when apipe is passed through the at least one gripper opening imparting littleresistance to the forward advancement of the pipe into the at least onegripper while imparting sufficient resistance to rearward movement ofthe pipe to prevent withdrawal of the pipe from the at least onegripper; and a stiffener positioned at least partially within the innercasing and the at least one gripper opening and aligned with the atleast one port opening, such that a pipe inserted into the at least onepipe port can pass through the inner casing over the stiffener andthrough the at least one gripper, wherein the stiffener has at least apair of sealing members each positioned within a groove in an outersurface of the stiffener such that when a pipe is passed over thestiffener and sealing members the sealing members can contact aninterior wall of the pipe to provide a seal between the pipe and thestiffener, and wherein the pair of sealing members have the samediameter and the grooves have different dimensions.
 2. The pipe fittingaccording to claim 1, wherein the pipe port further comprises at leastone gusset positioned on the elongated lip around the port opening. 3.The pipe fitting according to claim 1, wherein the at least a pair ofsealing members comprise elastomeric O-rings.
 4. A coupler comprising:an outer casing having first and second pipe ports each providing apassageway for a pipe to be passed into the outer casing, wherein eachpipe port comprises an elongated lip and a port opening forming at leastpart of the passageway; a hollow inner casing positioned within theouter casing and having a first opening and a second opening, wherein afirst inner casing opening is aligned with the first port opening andthe second inner casing opening is aligned with the second port opening;first and second grippers positioned within the inner casing, whereinthe first gripper has an opening aligned with the first pipe portopening and wherein the first gripper includes one or more reverseserrations that can flex when a pipe is passed through the first gripperopening imparting little resistance to the forward advancement of thepipe into the first gripper while imparting sufficient resistance torearward movement of the pipe to prevent withdrawal of the pipe from thefirst gripper, and wherein the second gripper has an opening alignedwith the second pipe port opening and wherein the second gripperincludes one or more reverse serrations that can flex when a pipe ispassed through the second gripper opening imparting little resistance tothe forward advancement of the pipe into the second gripper whileimparting sufficient resistance to rearward movement of the pipe toprevent withdrawal of the pipe from the second gripper; and a stiffenerpositioned within the inner casing and the first and second gripperopenings and aligned with the first and second pipe port openings, suchthat a pipe inserted into the first pipe port can pass through the innercasing over one end of the stiffener and through the first gripper, anda pipe inserted into the second pipe port can pass through the innercasing over another end of the stiffener and through the second gripper,wherein the stiffener has a first pair of sealing members and a secondpair of sealing members, wherein each sealing member in the first pairof sealing members is positioned within a groove in an outer surface ofthe stiffener such that when a pipe is passed over the stiffener andsealing members the sealing members can contact an interior wall of thepipe to provide a seal between the pipe and the stiffener, wherein eachsealing member in the second pair of sealing members is positionedwithin a groove in an outer surface of the stiffener such that when apipe is passed over the stiffener and sealing members the sealingmembers can contact an interior wall of the pipe to provide a sealbetween the pipe and the stiffener, and wherein each pair of sealingmembers have the same diameter and the grooves have differentdimensions.
 5. The coupler according to claim 4, wherein the first andsecond pipe ports further comprise at least one gusset positioned on theelongated lip around the port opening.
 6. The coupler according to claim4, wherein the pair of sealing members comprise elastomeric O-rings. 7.A coupler comprising: an outer casing having first and second pipe portseach providing a passageway for a pipe to be passed into the outercasing, wherein each pipe port comprises an elongated lip and a portopening forming at least part of the passageway; a hollow inner casingpositioned within the outer casing and having a first opening and asecond opening, wherein a first inner casing opening is aligned with thefirst port opening and the second inner casing opening is aligned withthe second port opening; first and second grippers positioned within theinner casing, wherein the first gripper has an opening aligned with thefirst pipe port opening and wherein the first gripper includes one ormore reverse serrations that can flex when a pipe is passed through thefirst gripper opening imparting little resistance to the forwardadvancement of the pipe into the first gripper while impartingsufficient resistance to rearward movement of the pipe to preventwithdrawal of the pipe from the first gripper, and wherein the secondgripper has an opening aligned with the second pipe port opening andwherein the second gripper includes one or more reverse serrations thatcan flex when a pipe is passed through the second gripper openingimparting little resistance to the forward advancement of the pipe intothe second gripper while imparting sufficient resistance to rearwardmovement of the pipe to prevent withdrawal of the pipe from the secondgripper; and a stiffener positioned within the inner casing and thefirst and second gripper openings and aligned with the first and secondpipe port openings, such that a pipe inserted into the first pipe portcan pass through the inner casing over one end of the stiffener andthrough the first gripper, and a pipe inserted into the second pipe portcan pass through the inner casing over another end of the stiffener andthrough the second gripper, wherein the stiffener has a first pair ofsealing members and a second pair of sealing members, wherein eachsealing member in the first pair of sealing members is positioned withina groove in an outer surface of the stiffener such that when a pipe ispassed over the stiffener and sealing members the sealing members cancontact an interior wall of the pipe to provide a seal between the pipeand the stiffener, wherein each sealing member in the second pair ofsealing members is positioned within a groove in an outer surface of thestiffener such that when a pipe is passed over the stiffener and sealingmembers the sealing members can contact an interior wall of the pipe toprovide a seal between the pipe and the stiffener, and wherein the pairof sealing members have the same diameter and the grooves have differentdimensions.
 8. The coupler according to claim 7, wherein each of thefirst and second pipe ports further comprises at least one gussetpositioned on the elongated lip around the port opening.
 9. The coupleraccording to claim 7, wherein each pair of sealing members compriseelastomeric O-rings.